A portrait of Syrian President Bashar al-Assad burns during clashes between rebels and Syrian troops in the city center of Selehattin, near Aleppo. (July 23, 2012) Photo Credit: Getty Images

Even though it has been an open secret for 40 years, Syria has always been studiously ambiguous about whether it has chemical weapons.

But this week, the Syrian government said it would deploy chemical weapons against any foreign -- presumably Western -- intervention in its civil war. The U.S. Department of State said this was "direct confirmation" that Damascus does indeed have a chemical-weapons arsenal.

Syria's Foreign Ministry was at pains to make clear that the weapons would never, under any circumstances, be used against the Syrian people. Aside from that reassuringly humane position, chemical weapons are poorly suited for the kind of hit-and-run, urban-guerrilla warfare Damascus is fighting.

The weapons are said to include mustard and sarin gases, as well as cyanide, and to be capable of being delivered by aircraft, surface-to-air missiles and rockets. Such weapons generally are most effective against massed formations in open country.

The timing of Syria's disclosure of WMD may be a sign of desperation by the Assad regime.

Randa Slim, a Syria expert for a Washington think tank, told The New York Times, "The chemical weapons remain one of the Syrian regime's strongest few trump cards, and they are threatening to use it in order to improve their rapidly weakening negotiating position." If any foreign power, Western or Arab, is planning to intervene militarily in Syria, word of it has not leaked out, and the countries capable of intervention all deny any such plans, especially now that the rebels seem more than able to hold their own.

How to secure those weapons remains a worrisome problem if the regime starts to crumble. Slim may be on to something when she suggests the chemical weapons are a bargaining chip.